Bicycle riding is valued as exercise for many reasons. It is an outstanding way to develop aerobic and anaerobic fitness, it is the basis of a popular competitive sport, it is relaxing and therapeutic, and it is also used as a typical workload in physiology research.
But when outdoor conditions are bad (rain, ice, chill, darkness) a rider's only option is to use a stationary indoor exerciser.
Known means of indoor pedaling include a purpose built ergometer; a rider's own bicycle on a fixed stand with inertia and wind resistance; a rider's own bicycle on rollers with occasional resistance add-ons; a rider's own bicycle held upright on rollers; a rider's own bicycle held upright on a treadmill; a rider's own bicycle riding freely on a level or sloped treadmill.
Such prior art pedaling exercisers fail to provide many of the benefits of actual outdoor riding, namely,
1. Side to side tilting. Few indoor exercisers allow a bicycle to tilt naturally in response to muscular effort or steering actions. Thus they engage different muscles in power production, and degrade balancing reflexes. (So-called ‘training rollers’ approximate natural leaning, but their balancing differs substantially from actual bicycle riding because the dual rear-wheel supports generate significant yawing moments; and the loosely coupled front-wheel roller is subject to stability-reducing speed changes from the horizontal force of a steered front wheel.)
2. High pedaling inertia. Few indoor exercisers have enough inertia to permit riders to exert the high forces of startup or sprinting, or to use the same pulsatile pedaling style that they find effective for ordinary riding. Thus low-inertia exercise bikes de-train the rider's pedaling habits. Furthermore coasting is less feasible, because the exercise bicycle quickly comes to rest. (A few indoor exercisers have large flywheels or electronic simulation of pedal inertia, but none of these allow tilting.)
3. Fore/aft acceleration. No indoor pedaled exercisers respond to pedal thrusts with actual rider acceleration, or respond to the intensity of effort with visual or kinesthetic clues of moving faster or slower. In actual riding, such accelerations and motions provide a very natural instinctive feedback on level of effort, and are highly motivational (through feelings of pleasure, or achievement) for maintaining a given effort.
4. Hills. Those who ride seriously know that the challenge of a hill adds unique motivation and enjoyment to a rigorous training ride. A few electronic-based exercisers purport to simulate ‘hills’, but these are merely increases in resistance, without the upward slope, or the enhanced rearwards acceleration when coasting. No indoor pedaled exerciser provides the actual sensation of riding up a hill.
5. Air resistance (speed-dependent resisting torque) forms a natural and realistic limit to pedaling speed. It is simulated by only some exercisers, and not in combination with the other desirable features mentioned above. Realistic speed-dependent resistance helps a rider fine-tune a ‘pace’ that develops maximum endurance.
Many would find value in a realistic indoor bicycle-riding simulation, which faithfully reproduces all the forces and dynamics of real-world pedaling when outdoor riding isn't practical. As a further advantage, realistic machine-based cycling would permit a coach or trainer to monitor and correct a competitor's actual performance, while his effort level is consistently controlled.
One known method of implementing a stationary bicycle is to ride a bicycle on a treadmill. Treadmills have a potential to make steering and balancing perfectly realistic. However, even if a large-enough treadmill can be found, simply riding on it has disadvantages making it untenable as a practical simulation. It is an aim of the current invention to eliminate those disadvantages.
One disadvantage of this approach stems from the lack of pedaling resistance. A bicycle rider frequently applies large pedaling torque for a few seconds, resulting simply in a modest change to bicycle speed. A free bicycle on a treadmill will quickly be ridden off the front.
Another disadvantage is the typical treadmill's speed-control operator interface. A user must typically adjust the treadmill control causing the treadmill to turn faster or slower, or must accept a schedule of speeds set at the beginning of the user's exercise session. It would be virtually impossible for a bicycle rider to place his bicycle on a standard treadmill and reach the control panel of the treadmill. Moreover, although it is fairly easy for a walking/running treadmill-user to regulate his speed well enough to stay on the treadmill, this presents a far greater challenge or frustration for a high-speed cyclist.
These disadvantages no doubt explain why many of the prior art solutions show a bicycle essentially bolted in place on a treadmill. But the sensations of riding a rigidly held cycle are so different from that of riding a cycle that is free of restraint that it would actually have a negative effect on the training of the cyclist's balancing reflexes and muscular usage patterns, as well as being less pleasant and motivational. Bolting in place eliminates desirable features such as lateral tilting and fore/aft acceleration. In addition the response to pedaling torque is generally an unrealistically fixed speed. Furthermore, bolting in place makes it inconvenient to switch bicycles.
What is needed is a treadmill system that permits lateral motion and tilting of the rider for realistic balancing and power production; fore/aft acceleration and displacement of the rider for feedback and motivation; resisting forces able to absorb any applied pedal torque (part of simulating inertia); and treadmill speed control providing appropriate belt acceleration and steady state speed based on the rider's both transient and sustained effort levels (simulating aerodynamic drag, and the other part of simulating inertia).